The present invention relates to an object detection apparatus, and more specifically to an object detection apparatus having a light intensifier tube which includes a shutter electrode, and which finds usefulness in viewing objects in environments having on the one hand, low ambient light, or on the other hand, other conditions which prohibit the timely, and effective imaging of the objects.
The prior art is replete with numerous examples of prior art image intensifying devices which have been incorporated into devices such as night vision scopes, laser range finders and other similar devices which have been used in various civilian and military applications.
As a general matter, many of these devices have included a light intensifier tube which transforms electromagnetic radiation which may, in some cases, not be visibly perceivable by the human eye, and which may be in selected wavelengths such as infrared, ultraviolet, or x-ray, and convert this same electromagnetic radiation into a visible image which then may be utilized by an observer for various applications. Yet further, these same light intensifier tubes may be designed to take ambient, visibly discernable electromagnetic radiation, and thereafter amplify it to create a visibly perceivable image which may be used by an observer to see an object of interest under poor visibility conditions.
The prior art light intensifier tubes, as a general matter, normally include a photocathode; an image intensification system; an anode and a luminescent screen. In this regard the photocathode is operable to transform the electromagnetic radiation forming the original optical image into an electronic image. The image intensifying system in these prior art devices is operable to take the electronic image, amplify it and then transfer it to the luminescent screen, where this image is then converted into a visibly discernable image which may be perceived by the operator of same. In this arrangement, electromagnetic radiation originating from the object of interest, or from another source, upon impacting the photocathode causes a resulting emission of electrons in the form of a photocurrent from the surface of same. The resulting photoelectrons formed by this process are accelerated and focused by the light intensifier tube. The focused photoelectrons bombard the luminescent screen and cause it to luminesce. In order to focus the photoelectrons to produce good useable images, the various prior art devices have utilized magnetic fields of various types, and other electrostatic-type lenses which are located between the photocathode and the anode. The aforementioned lenses are operable to collect the electrons emitted from the photocathode surface into narrow beams which reproduce on the luminescent screen in a visibly discernible image which closely replicates or corresponds to the image projected on the photocathode.
While these earlier prior art light intensifier tubes have operated with varying degrees of success, numerous shortcomings in their individual designs have detracted from their usefulness.
For example it has been observed, that the optical resolution capacity of these earlier prior art light intensifier tubes was somewhat limited by aberrations in the electronic lenses employed with same. Still further, it was observed that it was quite difficult to reduce optical aberrations to allowable ranges by changing the resulting geometry of any of the electrodes employed in these assemblies. Consequently, in the decades following the development of these aforementioned prior art devices, sophisticated second and third generation light intensifier tubes were developed which included the use of assorted fiber-optical electrodes, and microchannel plates of various designs. While these so-called multiple-stage light intensifier tubes significantly increased the brightness of any resulting image, further difficulties remained with the use of such devices for imaging objects where other competing light sources might also be in the general vicinity of the object being observed. In this regard, other bright light sources in the vicinity of the object being viewed would often cause the resulting image provided to the observer to be completely unusable. This has been known as the so-called xe2x80x9cBloom Effectxe2x80x9d. Various schemes and devices have been developed to reduce the bloom effect and this is shown more clearly in various prior art references such as U.S. Pat. Nos. 5,396,069 and 5,519,209 to name but a few.
As might be expected, while these various improvements have resulted in second and even third generation light intensifier tubes having improved performance characteristics, these improvements have significantly increased the difficulty in manufacturing same, and the resulting cost of the more recent light intensifier tubes when incorporated into various devices have placed them virtually out of reach for use in many industrial and other civilian applications. Consequently, their use has been confined, to a large degree, to mostly military and other law enforcement applications.
Accordingly, an object detection apparatus and accompanying light intensifier tube which achieves the benefits to be derived from the aforementioned technology, but which avoids the determents individually associated therewith, and which can be used in various civilian and other industrial applications to image objects of interest during reduced ambient lighting or other environmental conditions is the subject matter of the present invention.
A first aspect of the present invention relates to an object detection apparatus having a light intensifier tube which includes a photocathode; a luminescent screen disposed in spaced relation relative to the photocathode; a shutter electrode disposed intermediate the photocathode and the luminescent screen; and an anode located intermediate the shutter electrode and the luminescent screen.
Another aspect of the present invention relates to an object detection apparatus which includes a shutter electrode having an integral body which comprises a first cylindrical portion and a second cylindrical portion, each of the cylindrical portions having a predetermined diametral dimension, and wherein the first cylindrical portion is located adjacent the photocathode and wherein the diametral dimension of the first cylindrical portion is less than the diametral dimension of the second cylindrical portion.
Another aspect of the present invention relates to an object detection system which includes a light intensifier tube having a shutter electrode which has a first operational condition which permits electromagnetic radiation to be processed by the light intensifier tube, and a second operational condition which substantially prevents electromagnetic radiation from being processed by the light intensifier tube, and wherein the shutter electrode is placed in the first condition for a predetermined duration of time, and wherein the duration of time is adjustable.
Another aspect of the present invention relates to an object detection apparatus including a light intensifier tube which produces a visibly discernable light output from which information regarding the object of interest may be derived.
Yet a further aspect of the present invention relates to an object detection apparatus which includes a light intensifier tube having an adjustable shutter electrode, and wherein a charge couple device is provided and which is located in optical receiving relation relative to the visible light output provided by the light intensifier tube, and wherein the charge couple device produces an output signal from which information regarding the object of interest may be derived.
Another aspect of the present invention relates to an object detection apparatus which includes an operator display coupled in signal receiving relation relative to the electromagnetic radiation receiver, and which provides a visibly discernable image of the object of interest which may be viewed by the operator of the overland vehicle.
Still further, another aspect of the present invention relates to an object detection apparatus which includes a controller for simultaneously and selectively energizing an electromagnetic radiation emitter and adjustably controlling the discrimination of an electromagnetic radiation receiver.
Another aspect of the present invention relates to a sensor which is coupled in sensing relation relative to the overland vehicle and which provides information to a controller and which is utilized for adjusting the operation of the object detection apparatus.
Still another aspect of the present invention relates to an object detection apparatus which includes a sensor which is electrically coupled with a controller, and wherein the sensor provides information regarding ambient environmental conditions, and/or operational conditions of the overland vehicle and which effects the safe operation of the overland vehicle, and wherein the controller adjusts the operation of the object detection apparatus in a fashion appropriate to the sensor information.
Another aspect of the present invention relates to an object detection apparatus which includes a sensor borne by the overland vehicle and which is electrically coupled to a controller, and wherein the controller dynamically adjusts the operation of the object detection apparatus based upon information provided by the sensor.
Still a further aspect of the present invention relates to an object detection apparatus which includes an electromagnetic radiation emitter borne by the overland vehicle and which emits eye-safe electromagnetic radiation having predetermined wavelengths in a given direction toward an area of interest which is spaced a predetermined distance from the overland vehicle, and along a possible path of movement of the overland vehicle, and wherein the electromagnetic radiation emitted strikes an object located within the area of interest and is reflected back in the direction of the overland vehicle; a light intensifier tube borne by the overland vehicle and which is operable to selectively receive and amplify the reflected electromagnetic radiation emitted by the electromagnetic radiation emitter, and other electromagnetic radiation originating from other sources within the area of interest, and wherein the light intensifier tube has a first end and an opposite second end, and wherein an adjustable shutter electrode is made integral with the light intensifier tube, and further has a first operational condition which permits electromagnetic radiation to be amplified by the light intensifier tube, and a second operational condition which substantially prohibits the amplification of the electromagnetic radiation entering into the light intensifier tube, and wherein the electromagnetic radiation entering into the light intensifier tube in the first operational condition is amplified to provide a visibly discernable light output which is provided at the second end thereof; an optical filter disposed in optical filtering relation relative to the first end of the light intensifier tube, and which passes the electromagnetic radiation emitted by the electromagnetic radiation emitter, and which has the predetermined wavelength, and which are reflected from the object of interest which is located within the area of interest; a charge couple device coupled in optical receiving relation relative to the second end of the light intensifier tube and which produces an electrical output representative of the visibly discernable light output provided at the second end of the light intensifier tube; an operator display borne by the overland vehicle and which is coupled in receiving relation relative to the electrical output provided by the charge coupled device, and which produces a visibly discernable image of the object of interest within the area of interest; a controller borne by the overland vehicle and which simultaneously and selectively energizes the electromagnetic radiation emitter to produce discreet pulses of electromagnetic radiation, and further causes the shutter electrode to selectively assume the first and second operational conditions to facilitate the amplification of the reflected electromagnetic radiation originating from objects of interests located within the area of interest, and from other sources electromagnetic radiation located within the area of interest, and to simultaneously minimize the amplification of electromagnetic radiation originating from locations outside of the area of interest; and a control circuit electrically coupled with the controller and which causes the controller to adjust the distance that the area of interest is from the overland vehicle.
These and other aspects of the present invention will be discussed in further detail hereinafter.